Run the streams benchmark on this system and send the results. http://www.mcs.anl.gov/petsc/documentation/faq.html#computers
> On May 18, 2015, at 11:14 AM, venkatesh g <[email protected]> wrote: > > Hi, > I have emailed the mumps-user list. > Actually the cluster has 8 nodes with 16 cores, and other codes scale well. > I wanted to ask if this job takes much time, then if I submit on more cores, > I have to increase the icntl(14).. which would again take long time. > > So is there another way ? > > cheers, > Venkatesh > > On Mon, May 18, 2015 at 7:16 PM, Matthew Knepley <[email protected]> wrote: > On Mon, May 18, 2015 at 8:29 AM, venkatesh g <[email protected]> wrote: > Hi I have attached the performance logs for 2 jobs on different processors. I > had to increase the workspace icntl(14) when I submit on more cores since it > is failing with small value of icntl(14). > > 1. performance_log1.txt is run on 8 cores (option given -mat_mumps_icntl_14 > 200) > 2. performance_log2.txt is run on 2 cores (option given -mat_mumps_icntl_14 > 85 ) > > 1) Your number of iterates increased from 7600 to 9600, but that is a > relatively small effect > > 2) MUMPS is just taking a lot longer to do forward/backward solve. You might > try emailing > the list for them. However, I would bet that your system has enough bandwidth > for 2 procs > and not much more. > > Thanks, > > Matt > > Venkatesh > > On Sun, May 17, 2015 at 6:13 PM, Matthew Knepley <[email protected]> wrote: > On Sun, May 17, 2015 at 1:38 AM, venkatesh g <[email protected]> wrote: > Hi, Thanks for the information. I now increased the workspace by adding > '-mat_mumps_icntl_14 100' > > It works. However, the problem is, if I submit in 1 core I get the answer in > 200 secs, but with 4 cores and '-mat_mumps_icntl_14 100' it takes 3500secs. > > Send the output of -log_summary for all performance queries. Otherwise we are > just guessing. > > Matt > > My command line is: 'mpiexec -np 4 ./ex7 -f1 a2 -f2 b2 -eps_nev 1 -st_type > sinvert -eps_max_it 5000 -st_ksp_type preonly -st_pc_type lu > -st_pc_factor_mat_solver_package mumps -mat_mumps_icntl_14 100' > > Kindly let me know. > > Venkatesh > > > > On Sat, May 16, 2015 at 7:10 PM, David Knezevic <[email protected]> > wrote: > On Sat, May 16, 2015 at 8:08 AM, venkatesh g <[email protected]> wrote: > Hi, > I am trying to solving AX=lambda BX eigenvalue problem. > > A and B are of sizes 3600x3600 > > I run with this command : > > 'mpiexec -np 4 ./ex7 -f1 a2 -f2 b2 -eps_nev 1 -st_type sinvert -eps_max_it > 5000 -st_ksp_type preonly -st_pc_type lu -st_pc_factor_mat_solver_package > mumps' > > I get this error: (I get result only when I give 1 or 2 processors) > Reading COMPLEX matrices from binary files... > [0]PETSC ERROR: --------------------- Error Message > ------------------------------------ > [0]PETSC ERROR: Error in external library! > [0]PETSC ERROR: Error reported by MUMPS in numerical factorization phase: > INFO(1)=-9, INFO(2)=2024 > > > The MUMPS error types are described in Chapter 7 of the MUMPS manual. In this > case you have INFO(1)=-9, which is explained in the manual as: > > "–9 Main internal real/complex workarray S too small. If INFO(2) is positive, > then the number of entries that are missing in S at the moment when the error > is raised is available in INFO(2). If INFO(2) is negative, then its absolute > value should be multiplied by 1 million. If an error –9 occurs, the user > should increase the value of ICNTL(14) before calling the factorization > (JOB=2) again, except if ICNTL(23) is provided, in which case ICNTL(23) > should be increased." > > This says that you should use ICTNL(14) to increase the working space size: > > "ICNTL(14) is accessed by the host both during the analysis and the > factorization phases. It corresponds to the percentage increase in the > estimated working space. When significant extra fill-in is caused by > numerical pivoting, increasing ICNTL(14) may help. Except in special cases, > the default value is 20 (which corresponds to a 20 % increase)." > > So, for example, you can avoid this error via the following command line > argument to PETSc: "-mat_mumps_icntl_14 30", where 30 indicates that we allow > a 30% increase in the workspace instead of the default 20%. > > David > > > > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener > > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener >
